bgp soft reconfiguration inbound

Wolfgang Hennerbichler wh at univie.ac.at
Fri Nov 20 14:19:05 CET 2009


Fellow Bird Users, 

I thought our bird installation was ready for prime-time as one thing caught my eye which I don't like at all, but hopefully you can help me out - we do bgp connections like this (only necessary stuff displayed): 

protocol bgp R1120x193_203_0_25 {

  local as myas;
  neighbor 193.203.0.25 as 1120;
  password "xyz";
  import filter bgp_in_AS1120x193_203_0_25;
  export all;
  table T1120x193_203_0_25;
  rs client;
  start delay time 55;
}


filter bgp_in_AS1120x193_203_0_25
prefix set allnet;
{
  # ...
  allnet = [ 193.171.255.32/27, 193.171.255.64/27, 192.92.125.0/24, 194.0.0.0/24 ];
  if ! (net ~ allnet) then reject;
  accept;
}

Now I realized that if I changed the definition for 'allnet' and do a 'configure soft' these routes that are added or removed to 'allnet' are not rejected or added, because it seems that there is no bgp soft reconfiguration taking place (it works if I trigger a soft reconfiguration outbound on the peer router, or if I restart the protocol which causes bgp to flap). I know that nix.cz doesn't need this, as filtering is done in the pipe protocol, but we would really really like to filter at the very border, and if the filters change, I think a bgp soft reconfiguration inbound would be great. Is there a way to do a bgp soft reconfiguration, so that the routes are re-transmitted / re-calculated? 

Thanks for any help and have a nice weekend; 
Wolfgang

-- 
www.vix.at | www.aco.net
wh at univie.ac.at | WH844-RIPE
Vienna University Computer Center



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